Generally in the field of surgery, mechanical cutters utilizing a reciprocal or rotating cutting element have been used to sever tissue of a patient. Cutting devices that use light energy to cut tissue are also well known in the art. Electrosurgical devices for tissue excision or cauterization similarly have a long medical history. Such instruments have encountered numerous problems due to their one dimensional capabilities and have failed to meet many of the needs of a surgeon performing a surgical procedure. Thus, there is a requirement of a multiplicity of instruments which have to be sterilized after each procedure representing a significant cost as well as instrument down time and shortened instrument life span due to sterilization. The following patents constitute representative types of prior art instrumentation directed toward tissue removal.
U.S. Pat. No. 5,389,104 issued to Hahnen et al. discloses an arhroscopic surgical instrument which includes a hollow tube with an actuator coupled to its proximal end and an end effector coupled to its distal end. The actuator and the end effector are coupled by a cylindrical push rod that passes through the hollow tube. The push rod includes a frangible link in the form of a flattened portion with strength reducing semicircular side cuts which break when a predetermined force is applied to the end effector by the actuator. The end effector includes a stationary jaw and a movable jaw. An electrical connector is provided to the insulated hollow tube for supplying the jaws with a cautery current.
U.S. Pat. No. 4,499,899 to Lyons, III discloses a fiber-optic illuminated microsurgical scissors device. The rotary cutting scissors device incorporates an internal fiber-optic light source which constantly illuminates the line of cut by moving in tandem with the instrument during surgery.
Numerous mechanical cutters are described in the prior art. An example of a surgical mechanical cutting instrument is disclosed in U.S. Pat. No. 1,754,806 to Stevenson which is directed towards an instrument for operations on thin osseous tissue. Another surgical mechanical cutting instrument in the form of a disposable arthroscopic surgical instrument is described in U.S. Pat. No. 5,395,375 to Trukel et al. An endoscopic pericardial scissors is disclosed in U.S. Pat. No. 5,395,386 issued to Slater and another mechanical cutter in the form of a compound motion cutting device is set forth in U.S. Pat. No. 5,431,674 to Basile et al.
There currently exists a need for a device capable of providing the surgeon with a disposable sharp, sterile mechanical reciprocating or scissors blade cutting tip which simultaneously makes available to the surgeon the ability to quickly and conveniently cauterize tissue and/or excise tissue in situations in which reciprocating or rotating blade mechanisms are not preferred or are contraindicated. Present blade mechanisms have a life span ranging from 10 to 15 operations before the cutting blades become to dull or nicked to use. Traditionally the instruments are then thrown away or sent back to the manufacturers for refabrication. The present inventive device meets this need by providing the surgeon with a reusable or resposable shear housing which includes at least one throughgoing bore for a laser transmission cable and/or an electrosurgical wave form transmission cable. A disposable tip which is quickly attachable to and removable from the shear handle housing incorporates a mechanical reciprocating blade cutting mechanism and a laser delivery tip and/or an electrosurgical tip.
Although electrosurgical devices can be used to sever tissue, they cause damage and neurosis to surrounding tissues. Lasers and mechanical cutters provide the surgeon with a superior method of cutting tissue but a need to coagulate the tissue and blood vessels still exists. The mechanical cutter of this invention has a plurality of cutting means disposed at the distal end of a long disposable shaft. This design is frequently used in surgical procedures performed within the body through small openings in the body. The bleeding that normally accompanies any type of invasive surgery obstructs the surgeon's view and slows the procedure. Therefore, it is desirable to achieve hemostasis at the surgical site as quickly as possible to avoid prolonging the surgical procedure. The present invention allows this by providing the surgeon with a readily accessible means of stopping bleeding after an incision has been made. The surgeon need not stop the surgical procedure to reach for a second instrument to coagulate the tissue at the surgical site. In addition to the above-mentioned electrosurgical coagulation and cutting, the present invention affords the surgeon the opportunity to coagulate or incise tissue using a laser.
While some lasers are effective coagulators and cutters, certain other types of lasers, CO.sub.2 lasers for example, are effective at cutting tissue but are not good coagulators. It is desirable when using such devices to have a means for stopping bleeding because blood loss weakens the patient and obstructs the surgeon's view. Using separate hand pieces for cauterizing and cutting is, as previously mentioned, unwieldy and needlessly prolongs the procedure to the detriment of the patient. There are also situations in which the surgeon would like to use a mechanical cutter and a laser coagulator. Certain lasers are good coagulators but are poor tissue cutters. The YAG laser, for example, is sometimes used as a coagulator but is not considered to be a good tissue cutter. Similarly, a plurality of different types of electrosurgical coagulators are needed by surgeons depending on the type of surgery being performed. Monopolar, bipolar and resistive electrosurgical devices are capable of coagulating blood. All three types are included within the scope of this invention because they each serve different purposes. A heated implement can provide effective hemostasis only if small blood vessels have been severed, but if larger vessels are involved, a high frequency electrical current is preferred.
The mechanical cutting of the tissue at the surgical site is preferably performed by a pivoting cutter blade which attached to the distal end of the disposable tip. The lumen of this disposable tip can be used to provide a path or passageway from the housing to the distal end of the device for an optical fiber, electrical conductor strand, and if desired suction.